Laser Capture Microdissection is a technique developed at NIH to capture minute portions of tissue from histo-pathology slides for subsequent molecular analysis. A thermoplastic film in contact with a tissue specimen is selectively activated by a laser beam under microscopic control to bond with the desired tissue. Removal of the film separates the adhered tissue from that remaining on the slide, making it available for analysis. The technique enables the collection and processing of extremely homogeneous samples in a routine manner that does not require great manual dexterity. Over the past several years a number of refinements of the technique have been developed. We have perfected a cylindrical configuration which employs a line contact with the tissue to minimize contamination. This is capable of removing tissue fragments as small as 3 microns in diameter. We have further developed this into a non-contact system to optimize the system for single cell transfers. We are also developing a non-contact system utilizing a continuous tape of thermoplastic which is separated from the tissue by a gap of approximatly 5 microns. Contact between the tape and the tissue will only occur at the immediate location of the laser pulse. We hope to explore whether there are performance and economic advantages to using this alternative substrate. We are refining our thermal model which describes the process by which the laser energy is absorbed and diffused in the polymer in order to further predict tissue and film temperature transients as a function of the system parameters. - microdissection, laser- capture- microdissection, tissue- microdissection, lasers